CVE catalog
CVE-2026-19401
Any remote client can crash a (debugging/non-release build type) NSD serve child by sending it a special crafted message with a specially tuned number of DNS Cookie options (17 when UDP payload size i
- Severity
- High · CVSS 8.2
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - Published
- Updated
- Source
- [NVD] · [CVE record]
- EPSS
- 0.46% · Oct 25, 2026
Any remote client can crash a (debugging/non-release build type) NSD serve child by sending it a special crafted message with a specially tuned number of DNS Cookie options (17 when UDP payload size is 512). By continuously crashing the serve childs, the remote client can severely hamper or, when positioned sufficiently close, deny all DNS service.
Vulnerable and fixed packages
Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.
| Distribution | Package | Release | Version | Status |
|---|---|---|---|---|
| Debian | nsd | sid | 4.15.4-1 | fixed |
| Debian | nsd | forky | 4.15.4-1 | fixed |
| Debian | nsd | trixie | 4.12.0-1 | vulnerable |
| Debian | nsd | bookworm | 4.6.1-1 | vulnerable |
| Cpe | nsd | Not reported | 4.15.1 | fixed |
Fixed-version evidence
| Distribution | Package | Type | Release | Fixed version | Urgency | Origin | Bugs |
|---|---|---|---|---|---|---|---|
| Debian | nsd | source | sid | 4.15.1-1 | not yet assigned | Not reported | Not reported |
| Debian | nsd | source | forky | 4.15.1-1 | not yet assigned | Not reported | Not reported |
| Debian | nsd | source | trixie | (unfixed) | not yet assigned | Not reported | Not reported |
| Debian | nsd | source | bookworm | (unfixed) | not yet assigned | Not reported | Not reported |
| Cpe | nsd | cpe | Not reported | 4.15.1 | Not reported | NVD-CVE-2026-19401 | Not reported |
OpenFactory catalog packages
[Debian 12 (Bookworm)]
- [nsd]Affected
Details (2)
4.6.1-1· amd64 · bookwormAffected
nvd · nsd · debian · bookworm; nvd · nsd · debian · 12
4.6.1-1· arm64 · bookwormAffected
nvd · nsd · debian · bookworm; nvd · nsd · debian · 12
[Debian 13 (Trixie)]
- [nsd]Affected
Details (2)
4.12.0-1· amd64 · trixieAffected
nvd · nsd · debian · 13
4.12.0-1· arm64 · trixieAffected
nvd · nsd · debian · 13
Observed:
References
- [https://nvd.nist.gov/vuln/detail/CVE-2026-19401]
- [https://osv.dev/vulnerability/DEBIAN-CVE-2026-19401]
- [https://security-tracker.debian.org/tracker/CVE-2026-19401]
- [https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-19401.json]
- [https://wid.cert-bund.de/.well-known/csaf/white/2026/wid-sec-w-2026-3663.json]
[CERT-Bund public advisories] · [Debian Security Tracker] · [FIRST EPSS] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX]